Stability of alprazolam, chloroquine phosphate, cisapride, enalapril maleate, and hydralazine hydrochloride in extemporaneously compounded oral liquids

Abstract

The stability of five drugs commonly prescribed for use in oral liquid dosage forms but not commercially available as such was studied. Alprazolam 1 mg/mL, chloroquine phosphate 15 mg/mL, cisapride 1 mg/mL, enalapril maleate 1 mg/mL, and hydralazine hydrochloride 4 mg/mL were each prepared in a 1:1 mixture of Ora-Sweet and Oral-Plus (Paddock Laboratories), a 1:1 mixture of Ora-Sweet SF and Ora-Plus, and cherry syrup and placed in 120-mL amber clear polyethylene terephthalate bottles. Three bottles of each liquid were stored at 5 °C and three at 25 °C, all in the dark. Samples were taken initially and at various times up to 60 days for analysis by high-performance liquid chromatography and assessment of appearance and odor; pH was measured. A mean of at least 91% of the initial drug concentration was retained for 60 days in the alprazolam, chloroquine phosphate, cisapride, and enalapril maleate liquids. The hydralazine hydrochloride liquids retained more than 90% of the initial concentration for only one day at 5 °C when prepared with Ora- Sweet-Ora-Plus and two days when prepared with Ora-Sweet SF-Ora-Plus and for less than a day in these preparations at 25 °C and in cherry syrup at 5 and 25 °C. No substantial changes in the appearance, odor, or pH of any liquid were observed. Alprazolam 1 mg/mL, chloroquine phosphate 15 mg/mL, cisapride 1 mg/mL, and enalapril maleate 1 mg/mL were stable in three extemporaneously compounded oral liquids for 60 days at 5 and 25 °C; hydralazine hydrochloride 4 mg/mL was stable at 5 °C for one day in Ora-Sweet-Ora Plus and for two days in Ora-Sweet SF-Ora-Plus.